Circuit breaker operating system



Inventors: Alexander C. Boisseau, BeTLiemTliTwv 5. Beall, Edward J. Frank, Roger- W. Lowery,

Their- Attorheg.

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CIRCUIT BREAKER OPERATING SYSTEM 3 Sheets-Sheet 3 Filed Nov. so, 1944 Fig.

Inventors:

i Patented Oct. 5,

CIRCUIT BREAKER OPERATING SYSTEM I Alexander C. Boisseau, Lansdowne, Benjamin 8.

Beall, Upper Darby, Edward J. Frank, Springileld, and Roger W. Lowery, Aidan, Pa., assignors to General Electric Company, a corporation of-Nw York Application November so, 1944, serial Nc. 565,634

Our invention relates to circuit breaker operating systems, and more particularly to a sys- 9 Claims. (Cl. 20o-81.4)

tem for effecting high speed operation of circuit l `breakers controllingl large amounts of electrical energy. Specifically our invention is .an improvement on copending Thumim etal. application, Serial No. 367,789, filed November 29, 1940, and assigned to the same assignee as the present application.

In order to eliminate the `fire hazard, circuit breakers havebeen satisfactory designed which do not utilize oil or other inflammable liquid for arc-extinguishing purposes but instead employ a blast of fluid.. such as air or other gas, to, extinguish the arc formed both when the circuit is broken between the relatively movable contacts of the circuit breaker and also during the closing operation of the circuit breaker to prevent the formation of any arc at this time. However, the value of any circuit breaker, whether or not it be of the fluid-blast type. lies in its ability to interrupt a circuit at the proper time and in the proper manner. Without a satisfactory operating and control system for such a circuit breaken.y

its value is largely lost for, if the control of the circuit breaker in the manner intended is not obtained, many undesirable conditions may result. Numerous control systems have been designed for satisfactorily controlling circuit breakers of the fluid-blast type. Our invention is specifically concerned with providing an operating -or control system for a gas-blast circuit breaker which controis larger amounts of electrical energy than were heretofore thought possible, such asin the neighborhood of three and one-half million kva. or more. When such circuit breakers are used on high-voltage systemsl because of the necessity. of providing sumcient electrical clearance between phases, it is customary to design them as single-pole units and to use a plurality of these units for a polyphase circuit breaker. It becomes necessary, therefore, to operate and interlock these units so that they will act as a single circuit breaker. I t Accordingly it is an object of our invention to provide a new and improved operating system for an electric circuit breaker capableof controlling large amounts of electrical energy which is rugged in construction, simple in design and provides satisfactory operation in every respect.

2 Further objects and advantages of our invention will become apparent as the following description proceeds and the featuresk of novelty which characterize our invention will be pointed out with particularly in the claims annexed to and forming a part of this specification.

For a better understanding of our invention reference may be had to the accompanying drawings in which Fig. 1 is a perspective view of a commercial embodiment of an' electric circuit breaker embodying our invention; Fig.` 2 is a sche atic diagram, partly in section, of the circuit reaker operating system embodying our in- `lvention showing primarily the pneumatic and mechanical connections with the electrical connections omitted for the sake of simplicity: and

Fig. 3 schematically illustrates the electrical circuits for the operating system disclosed in Fig. 2. A

Referring now to Fig. 1 of the drawing, there is illustrateda polyphase circuit breaker generally indicatedV at i comprising a plurality of single pole units 2; 3 andfl, respectively. Each Yof these units. 2, 3 and 4, includes a pair of relatively separable arcing or interrupting contacts schematically illustrated at 5 and 6 in Fig. 2. Each set of'arcing or interrupting contacts associated with the respectiveinterrupting units 2, 3 and l, is serially connected with a set of isolating contacts ythe movable contact arms of which are designated as 1, 8 and 9, respectively. Each of the interrupting units 2, 3 and lf'is supported from a frameworkgenerally indicated at I0 by a tripod arrangement of insulators designated at il, the poles 2, 3 and 4 being spaced the desired distance for proper electrical clearance. Isolating contact arms 1, 8 and 9 are pivotally mounted on horizontal pivots generally indicated at i2 and are gear-driven from rotatable insulators i3, one

It is another object of our invention to provide associated with each disconnecting contact arm 1, 8 and 9. Each disconnecting contact arm is adapted to engage with a cooperating stationary contact designated by the numeral i4 mounted on a suitable insulator i5 supported from framework Ill.- Each of the contacts il is electrically connected to an associated line terminal i6. The other line yterminals i1 for the various poles of the polyphase circuit breaker are indicated as extending from the top of each interruptingunit 2, 3 and l.

these tanks are interconnected by. a conduit 2i shown in Fig. 2. The operating and control system of our invention is also mounted on framework I6 and will be described in greater detail hereinafter. It will be observed that the polyphase circuit breaker employing the operating mechanism of our invention is particularly adapted for installation out of doors, in which case the'isolating contacts comprising external switch blades or contact arms 1, 8 and 9 may be constructed in accordance with the invention disclosed and claimed in copending application Serial No. 559,064, filed October 17, 1944, Frank and Fitzpatrick, now Patent Number 2,426,0094 issued August 19, 1947, assigned to the same assignee as the present application.

The specific construction of the circuit interruptlng units 2, 3 and 4 schematically illustrated in Fig. 2 forms no part of our invention but is disclosed and claimed in the copending application of Alexander C. Boisseau and Benjamin S. Beall, Serial-No. 570,006, flied December 27, i944, now Patent Number 2,444,765, issued July 6, 1948, assigned to the same assignee as the present application. Each of these interrupting units is identical and interrupting unit 3` which has been shown in section will be briey described in order more fully to appreciate our new and improved operating and control system therefor. Interrupting head or unit 3, as is mentioned above, comprises an insulating chamber 22 Withinwhich relatively m-ovable contacts and 6 are mounted. Both contacts 5 and 6 havebeen illustrated as movable contacts biased to the closed position by means of springs 23 and 24, respectively. In the closed position of the circuit breaker contacts v5 and 6 are in electrical engagement as shown in Fig. 2 and the contact 5 extends through a nozzle 25 while the contact 6 extends through a nozzle 26. Associated with contact 5 is a iiuid motor comprising piston 21. Similarly, associated with contact 6 is a fluid motor comprising piston 28. Pistons 21 and 28 are reciprocal within cylinders suitably mounted in arc extinguishing chamber 22. In the case of circuit interrupting unit 3 fluid under pressure is supplied from the source comprising tank i9 through a relatively short conduit 29 to arcing chamber 22, conduit 29 being branched as indicated at 30 and 3| so as to supply fluid under pressure ahead of each nozzle 25 and 26. The flow of, this fluid under pressure, which is preferably air, is controlled by a blast valve generally indicated at 32 closely associated With tank 9. When blast valve 32 is opened contacts 5 and 6 are retracted through nozzles 25 and 26 and a blast of uid through each nozzle quickly extinguishes the arc drawn between contacts 5 and E. The fluid blast exhausts to atmosphere 4 application, Serial No. 529,670, Boisseau, nled April 5, 1944, now Patent Number 2,445,558, issued July 20, i948, and assigned to the same assignee as the present application. This mechanism comprises a simple, longitudinally reciprocal operatin! rod 38 which extends between the outermost poles 2 and 4 of the circuit breaker and which will permit any spacing, such as 20 or more feet betweenpoles. At each-end of operating rod 25 is a rack 36. A similar rack 31 is also provided intermediate the ends of rod 35. are Y, adapted to engage spur sears 38, which through mtatable insulators I3 are drivingly connected with bevel gears 99 which mesh with bevel gears 40 rotatably mounted with disconnecting arms 1, 8 and 9, respectively, about horizontal axes |2. It will be obvious that movement to the left of rod Il, as viewed in Fig. 2, will cause the racks 26 and 31 to rotate spurgears 26 and to cause; simultaneous opening of the disconnecting contacts `of all of the poles of the multipole circuit breaker through simultaneous operation of disconnecting arms 1. 8 and 9.

Any suitable means may be provided for causing reciprocal -movement ofy operating rod 95. In viewof the fact thatfiuid under pressure is already provided in tanks I8, |9 and 26, a fluid operated means for operating rod 25 is preferable, and we have illustrated a circuit breaker opening fluid motor comprising piston 4| and cylinder 42 associated with the left-hand end of operating rod 35. A closing fluid motor comprising piston 43 and cylinder 44 is associated with the righthand end of operating rod 35., With this arrangement, as is disclosed and claimed in the above mentioned copending Boisseau application, Serial No, 529,670, substantially only tensile forces are applied to operating rod 25 which, accordingly, may be of relatively light construction; The circuit breaker opening iluid motor comprising cylinder 42 and piston 4| is connected through conduit 45, circuit breaker opening valve generally indicated at 46, and conduit 41, to tank I9. Similarly, the circuit breaking closing fluid motor comprising piston 43 and cylinder 44, is connected through conduit 46, circuit breaker closing control valve generaily indicated at 49, and conduit 41 with tank I9.

It is essential that the arcing contacts 5 and 6 in each of the interrupting units 2, 3 and 4 of the polyphase circuit breaker are separated and a blast of arc extinguishing air or gas belpresent adjacent a'll of the separated contacts before the through conduit 33. It should be understood that the interrupting units 2 and 4 are also connected by conduits 29 with tanks I6 and 20, respectively. Similarly, a blast valve 32 is associated with each conduit 29. These conduits are all preferably short and of equal length to insure equal intensity and timing of the fluid blasts.

The electrical circuit for each pole of the circuit breaker is completed between terminals |6 and I1 by stationary isolating contact 4, isolating or disconnecting arms, such as 1, 8 or 9, conductor 34, and interrupting contacts 5 and 6.

I'he disconnecting contact arms 1, 8 and 9, are

preferably operated as a unit after the interrupting contacts have functioned. The operating mechanism for these disconnecting contacts has been illustrated as identical with the operating mechanism disclosed and claimed in copending disconnecting contact arms'l, 8 and 9 are operated. Since each of the sets of disconnecting contacts are individually operable a suitable interlocking means should be provided between the circuit breaker opening control valve 46 and blast valves 32. Such an interlocking means is disclosed and `claimed in the above mentioned Thumim et al. copending appli-cation, Serial No. 367,789. In thedrawing we have schematically illustrated a pneumatic interlock generally designated at 50 which is essentially the ysame as the pneumatic interlock in the above mentioned Thumim et al.l application. The pneumatic interlock 50 comprises three identical cylinders 5|, 52 and 53 within which are mounted three identical pistons 54, 55 and 56, respectively. Springs 51 act against one face of pistons 54,55 and 56 to maintain them in the position indicated in Fig. 2.

These racks.y

audace generally indicated at 88 to opening control valve 48. With the pistons 8i, 82 and 88 in the normal spring biased position shown in Fig. 2, the ports connecting conduits 82 and 88 with the assov ciated cylinders are in free communication to atmosphere via the large ports 8i. When al1 of the blast valves 82 are opened and fluid under pressure is flowing in each of the conduits 28,

pistons 84, 88 and 88 are driven upwardly as.

position indicated, as will be more fullydescribed 4 hereinafter. f

From the foregoing description it will be obvious that pneumatic interlock 88 will not permit operation of circuit breaker opening valve 48 until all three pistons 84, 58 and 88 have been moved upwardly beyond all oi the ports leading to conduits 82 and 88. If for example, only pis- Y tens 84 and 88 move upwardly while piston 88` remains in the position indicated due to'failure of the blast valve 82 associated with interrupting unit 4, then the fluid under pressure in conduits Y88 and 88 will pass through conduits 88 and 82 and thence to atmosphere through port 8| of cylinder 88. It is obvious then that pneumatic interlock 88 positively prevents the opening of the isolating contacts comprising contact arms 1,'8 and 8 unless all the blast valves 82 have operated and fluid under pressure is flowing in each of the conduits 28. In other words, circuit breaker opening valve t8 cannot be operated tol the opening position to cause simultaneous operation of all of the disconnecting arms 1l 8 andf 8 until a blast of fluid under pressure is assured within all of the interrupting units 2. 8 and 4,

or until the arcs are extinguished at all] of the interrupting contacts.'

Itis usually desirable to lock the operating mechanism of the electric circuit breaker in either its open or its closed position. The locking means for this purpose must be such that it is released prior to the application of any force tending to separate the contacts of the circuit breaker. For this purpose we have illustrated a lock-open means 88 and a lock-closed means 81 arranged in close proximity to the rack 81 associated with interrupting unit 8. Locking means 88 and 81 are substantially identical, lock-open lmeans 88 comprising a locking member 88 pivotally mounted at 88 and connected through a crank arrangement to a piston 18 reciprocally mounted in a cylinder 1i. A spring 12 biases piston 18 and consequently locking member 88 into its locking position which is in engagement with roller 18 associated with the rightf-hand end of rack 31. When the circuit breaker is in other than its fully open position the rack 81 maintains the locking member 88 in the depressed position indicated in Fig. 2. The cylinder 1| of lock-open means 88 is connected by means of a conduit 1t with the conduit 48 supplying the circuit breaker closing fluid motor so that whenever the circuit breaker closing valve 48 is opened fluid under pressure will be admitted to cylinder 1| of the lock-open means" to move locking member 88 to its released position. A crank arm 18, the purpose of which-will be brought out in. the description included hereinafter, is flxedly mounted with locking arm 88 so as to also be rotatable aboutplvot 88.

Lock-closing means 81 comprises a locking arm 18 pivotally mounted about a shaft or pivot 11 and connected by suitable crank means to a piston 18 reciprocal in a cylinder 18. A spring 88 biases piston 18 and consequently locking member 18. into its locking position as shown in Fig. 2, which is in engagement with roller 8| associated with the left-hand end of rack 81. When the circuit breaker is in other than its fully closed position the rack 81 maintains the latching arm 18 in a depressed position analogous to the position of locking arm 88, shown in Fig. 2. The.` cylinder 18 of lock-opening means 81 is connected by means of a conduit 82 with the conduit 48 leading to the circuit breaker opening fluid motor so that whenever the circuit breaker opening valve 48 is opened fluid under pressure will be admitted to cylinder. 18 of lock-open means 81 to move locking arm 18 to its released position.

A crank arm 88. the purpose of which will be brought out in the description hereinafter, is rotatable about shaft 11 in fixed relationship with respect to locking arm 18.

If desired suitable dashpot means, generally indicated at 84 and 88 in Fig. 2, may be provided one at either end of operating rod 88. The dash pot means 84 is illustrated as being engageable by the rack 88 associated with interrupting unit 4 to cushion the operating mechanism as the circuit breaker reaches its closed position. Similarly. the dashpot means 88 is engaged by the rack 88 associated with interrupting unit 2 to cushion the operating mechanism as the circuit breaker reaches its open position.

Preferably the movement of operating rod 85 may be used to control limit switches. Accordingly we have illustrated a circuit breaker "a" switch 88, associated withthe left-hand rack 88. which is closed when vthe circuit breaker is closed and open when the circuit breaker is open. Slm-` ilarly, a "b" switch 81 is provided adjacent the right-hand rack 88 so as to be open when the circuit breaker is closed and closed when the circuit breaker is open. These limit switches 88 and 81 are operated by the racks 88 in a manner which is obvious from Fig. 2.

Operating rod 88 may also control the closing cut-off switch generally indicated at 88. This closing cut-off switch 88 is in many respects substantially identical with the closing cut-off switch disclosed and claimed in Boisseau Patent 2,348,147, granted April 11, 1944, and assigned to the same assignee as the present application. This closing cut-ofi' switch comprises an electromagnet includingmagnetic core 88 having associated therewith a winding 88. In addition this electromagnet also includes a. pair of pivotally mounted armatures 8| and 82. These armatures are normally biased away from core 88 by springs 88 and 84, respectively. Armature 8i is a relatively light armature which always is within the coercive range of the electromagnet associated therewith,while amature 82 is a heavy armature which can be moved outside the coercive range of theassociated electromagnet when iree to move under the inuence oi' spring 94. When armature 9| is moved into the position indicated in Figs. 2 and 3 it closes a set of contacts 99. On the other hand. when armature 92 is moved under the iniluence oi spring 9E to its extreme position it closes contacts 00. The armature 92 may be moved to the position indicated in Fig. 2 by two different means. The first of these means is a mechanical means and comprises a lever 91 rotatable with locking arm 16. When locking arm 16 moves to its locking position indicated in Fig. 2, arm 01 moves amature 92 to the position indicated in Fig. 2 whereby it may be held in that positionby the energization of winding 90. The second means for moving armature 92 into the coercive range of the associated electromagnet is a pneumatic means comprising piston actuated plunger 98 reciprocal in a cylinder 99 connected to conduit B2. Plunger 98 is normally biased by a spring i@ to the position indicated in Fig. 2. Whenever circuit breaker opening valve 46 is open, fluid under pressure from tank I9 moves piston operated plunger 98 into engagement with an extension |0| of heavy armature 92 so as to move armature 92 to the position indicated in Fig. 2. For a more detailed description of closing cutoil switch 38 attention is directed io the above mentioned Boisseau Patent 2,346,147.

As has been mentioned above, in order that relatively short air blast conduits 29 of equal length may be utilized to provide substantially equal fluid blasts at the interrupting units 2, 3 and 4, three similar individual blast valves 32 vare provided. It is desirable that these three blast valves are operated simultaneously and to this end a control arrangement therefor which will be described in greater detail hereinafter is provided.

The blast valves 32 are very similar to the blast valves disclosed in United States Letters Patent 2.315,991, Thumim, granted April 6, 1943, and as` signed to the same assignee as the present application. Since the three blast valves 32 are all identical, only one of them, namely the one assof ciated with interrupting unit 3, has been shown in section. Each of the blast valves 32 comprises a valve member |02 adapted to control the flow of fluid from the source such as tank i8 to conduit 29. Valve member |02 is connected to a piston |03 reciprocatingly mounted in a cylinder |04 formed integrally with the body of the blast valve 32. Suitable spring means |05 tend to bias valve member |02 to a closed position. To open blast valve 32 a pilot valve generally indicated at |06 is provided which allows fluid such as air under pressure from tank I9 to enter cylinder |00 above piston |03 through conduit |01. This fluid under pressure, by virtue of the larger area of piston |03 relative to the area of valve member |02` forces valve member |02 away from its seat io provide a path between source I9 and interrupting unit 3 or between sources I3 and 20 and interrupting units 2 and 4, respectively, in the case of the other poles of the circuit breaker.A

lluid such as air or gas in the space below piston |03 is vented through port |08 so that high speed operation of the blast valve 32 may be obtained. When pilot valve |06 is closed the spacein cylinder |04 above piston |03 is vented to atmosphere through a port |09 in pilot valve |06 so that air under pressure, which is admitted below piston |03 through port |03, forces the valve member |02 to its closed position. By this arrangement both opening and closing of the blast valves 32 is rapid and positive due to the action of fluid under pressure onboth sides of pistons |03.

Pilot valve |06 has been illustrated as oi the balanced pressure type'including a piston H0. Operation of pilot valve I 06 is obtained through operation oi' a control valve member I. Whenever control valve member is opened the pressure acting on piston |0 is unbalanced and pilot valve |06 is moved to the open position. The control valve member for each blast valve 32 is adapted to be operated either electricallyl or pneumatically and accordingly is connected to a piston ||2 reciprocal in a cylinder H3. A solenoid comprising an armature ||4 is also connected to control valve l5 biases control valve member I to the closed position. The solenoid comprising armature ||4 for the blast valve 32 includes a winding ||1. The solenoids comprising armatures ||4 associated with the blast valves 32 i'or controlling the blast fluid in the outer interrupting units 2 and 4 include windings ||6 and |I8, respectively, which windings are also illustrated schematically in Fig. 3 and will be described in greater detail in connection with the control circuit therefor. A pneumatically operated blast valve seal-in switch 9 for controlling contacts |20 is provided adjacent blast valve 32 associated with interrupting unit 2. Whenever blast valve 32 associated with interrupting unit 2 is open fluid under pressure flowing in conduit |01 will cause ililzast valve seal-in switch ||9 to bridge contacts In order to be sure that the circuit interrupter is notoperated unless the pressure in tanks it, I9 and 20 which are suitably interconnected by conduit 2| is sufficiently high, we have provided a plurality of pressure responsive switches |2|, |22 and |23, respectively. Pressure responsive switch |2| is a minimum opening pressure switch and is closed when the pressure falls to a value below which it might be unsafe to open the circuit breaker. Pressure responsive switch |23 is the minimum closing pressure responsive switch and is arranged to close its contacts when the pressure drops below a value somewhat above the value for which switch |2| is set. Pressure responsive switch |22 is the minimum reclosing pressure responsive switch which closes its contacts when the pressure falls to a` value somewhat above the pressure at which the relay |23 closes its contacts. Ii minimum opening pressure responsive relay |2| is set to close its contacts at pressures below 290 pounds per square inch, then minimum closing pressure responsive relay |23 will clcse its contacts when the pressure falls below 295 pounds per square inch, and

. minimum reclosing pressure responsive devis.

|122 will close its contacts when the pressure falls below 330 pounds per square inch. The reason for this is obvious since a greater amount of fluid under pressure is require-d to close and open the circuit breaker than merely to open the circuit breaker,and likewise a still greater amount of fluid under pressure is required to safely open, reclose and open the circuit breaker than in either of the other situations.

The pistons ||2 associated with each control valve for blast valves 32 may be simultaneously operated by a manual trip device of our invention generally indicated at |24. This manual trip device |24 controls the flow of fluid under pressure from one of the tanks such as 20 through conduits |25, |26, |21, and |23 to the A suitable spring y pistons ||2 of the control valves III for each of the blast valves 32. It should be understood that Fig. 2 is a diagrammatic representation of our invention and the manual trip device |24.. i is so arranged as to produce substantially simuliliary switch |33 which closes contacts |33 when' hand trip rod |.3I is in the normal position shown and opens contacts. |33 when the hand trip rod I'3| is pulled to the left, as viewed in Fig..2. Manual trip device |24 also includes a cylinder |31 within which is reciprocally mounted main lhand trip valve |33 which is essentially in the i'orm oi.' a large piston having Van extension in the form of a small piston |33 biased to close a port |40 by virtue of spring means |4I. Whenever manual pull rod I3 I is actuated to open valve |23 iiuid under pressure is permitted to ilow into port |40 and into an expansion tank or surge chamber |42. If the fluid pressure is sulciently high for safe operation, for example 290 pounds per square inch relativ to values enumerated above. small diameter piston |33 is lifted against the bias of spring |4I, accompanied by an inliux oi' pressure air below the main hand trip .valve or large piston |33 that is eifective to raise tl e piston valve high enough to permit' iiuid under pressure to enter conduit |23 so that pistons ||2 litt the control valves and cause substantiallyesimultaneous opening-of the three blastV l air or fluid under pressure during a hand trip operation, the handtrip piston valve |33 is closed mechanically during the initial motion or the isolating switch mechanism. This is accomplished by providing a cam |44 rotatable with one of tbe insulators I3 speciilcally illustrated in Fig. Zas

a contact |43. Switching arm |41 is normally biased to the open position by means of a spring |43. A lever |30 pivotally mounted at |3| and having mounted thereon a dog |32 controls the opening and closing oi switch |41. Lever |30 is connected by link |33 to spur gear 33 associatcd with interrupting unit 2. With this arrangement, as is fully described in the above mentioned Schneider patent. the blast valve cutoi! switch |43 operates early during both the closing and opening strokes of the disconnecting contact arms ,1. 3 and I3.

The circuit breaker opening valve 43 and the circuit breaker closing valve 43 are fvery similar to the pilot valves |03 f or controlling the blast valves 32. Circuit breaker opening valve 43 cornprises( a main valve member |34 connected to a piston |53 and biased to the closed position by means of' a springi33. VWhen the valve member |34 isin the closed position indicated conduit 43 is connected to atmospherethrough a port |31 which is closed by a valve member |53 when valve member |34 is open. l Opening valve 43 is of the balanced pressure type `and is opened by operation of a pilot valve member |53 which opens port |30 releasing to atmosphere the fluid under pressure acting on one side of piston |33. f Circuit breaker closing valve 43 is identical with circuit breaker .opening valve 43 as described thus far and the corresponding parts thereof are designated by the same reference numerals.

Pilot valve member |33 of c rcuit breaker closing valve 43 is operated by a lenoid comprising winding |3I. A spring |32 biases the armature of pilot valve |33 associated with solenoid winding |3I in a downward direction to close pilot valve member |33. A pneumatic seal-in switch for circuit breaker closing valve 43 is provided comprising switch'member |33 for controlling contacts |34. Seal-in switch |33 is connected to a piston |33 reciprocal in a cylinder |33. Cylinder |33 is connected to conduit 43 so that whenever circuit breakerfclosing valve 43 is opened, pneumatically operated seal-in switch |33 bridges contacts |34.

The pilot valve member |33 of circuit breaker opening valve 43 is pneumatically operated by means of a piston |31 connected thereto. which with the insulator I3 associated with the isolating contact arm 3. Cam |44 is engageable with roller |43 connected with piston or hand trip valve During anormal circuit interrupting operation. it is desirable i'rom the standpoint of conserving air to close the blast valves 32 as soon as the disconnecting contacts begin to open. Accordingly we have provided ya blast valve cut-oi! switch generally indicated at |43 which is closed when thefcircuit breaker is closed and which opens as soon as the disconnecting contact arms 1, 3 and I3 begin` to move. Blastvvalve dcut-oil.' switch |43 is substantially identical to the auxiliary switch disclosed and claimed in United` States Letters Patent 2.362.313, Schneider. grantedl November 7. 1344. and assigned to the same assignee as the present application. Blast valve cut-oII switch |43 comprises a pivotally mounted' switching arm |41 adapted to control pilot valve member |33 of circuit breaker opening valve 43 to the closed position. Whenever pressure is built up in conduit 34 and isolating switch reclosing interlock valve 33 is in the normally open position indicated in Fig. 2. pilot valve member |53 is opened to open circuit breaker opening valve 43. Pilot valve member a|33 when once opened is held in the open position by a mechanical latching member |10 engaging the member |1I connected to movable piston |31. A spring |12 biases latching member |10 into its latching position. The circuit breaker opening valve 43 is closed when the circuit breaker isolating contacts reach Vtheir 'fully open' position and locking arm 33 movesinto engagement with roller 13 under the influence of spring .12. This is accomplished by means oi' a rod |13 attached to piston 10A which is engageable with an extension 1|14 of latching means |10 to release latching means |10 andv consequently cause circuit breaker opening valve 43 to close by closing associated pilot valve member |33. The circuit breaker opening valve 43 and its opening and closing control is not our invention but is disclosed and claimed in copending application s. N.` 335.835,1irankA et' al.. filed. November 30.

adapted to operate as a reclosing circuit breaker, I,

and accordingly there is provided a control arrangement by means of which the circuit breaker may be operated as a reclosing breaker. lfIt will be understood by those skilled in the art that reclosing operation of the circuit breaker, as disclosed in the drawings, may be obtained by pre- 12 i winding |18. Fourthly, the pneumatic reclosing relay |18 must restore the switches |80, |8| and |82 to their normal position indicated in Fig. 2 at the end of the pneumatic reclosing relay cycle,

'say approximately one second, or 60 cycles, in

preparation for a possible repeat reclosing cycle. The pneumatic reclosing relay |18 will only be briefly described hereinafter since its specific construction forms no part of our invention but is disclosed and claimed in copending Boisseau and Beatty application, Serial No. 565,833, filed November 30, 1944, and assigned to the same assignee as the present application.

The pneumatic reclosing relay' |18, schematically illustrated in Fig. 2, comprises a plurality ton |85 is reciprocal in cylinder |83 while an ordi- I nary piston |88 is reciprocal in cylinder |84.

will immediately reclose upon cessation of the interrupting blast. The electrically operated isolating switch reclosing interlock valve 85 including a solenoid |15 having a winding |18 is adapted to prevent isolating contact arms` 1, 8 and 9 from operating. Normally, isolating switch reclosing interlock valve 85 is open so that uid under pressure in conduit 84 is free to open pneumatically operated circuit breaker opening valve 46. Il, however, winding |18 associated with isolating switch reclosing interlock valve 85 is energized the interlock valve 88 is closed to block the flow of fluid in conduit 88 to circuit breaker opening valve 48 which accordingly cannot be operated. Solenoid |15 also controls a switch |11 normally bridging contacts |18.

The reclosing-trip operation of a circuit breaker consists of two successive openings of interrupting contacts 5 and S followed by opening of the isolating contacts. It will be understood that the interrupting contacts might be opened and reclosed more than two times before the isolating contacts are opened. However, we prefer to provide only two successive operations of the interrupting contacts before the isolating contacts are operated, and to this end thereis provided a pneumatic reclosing relay generally indicated at |18. This pneumatic reclosing relay controls the time which is permitted to eiapse between the opening and reclosing of the interrupting contacts and furthermore conditions the reclosing control circuits for the opening operation of the isolating switch that sequentially follows the first reclosing operation if a persistent fault is present. Actually pneumatic reclosing relay |18 performs four separate functions. First, it deenergizes the blast valve windings H6, ||1 and ||8 by opening the normally closed switch |80 whereby the interrupting contacts 5 and 6 may reclose in response to a cessation of the fluid blast. Secondly, pneumatic reclosing relay |19 assures reestablishment of a circuit for energizing blast valve windings i6, |1 and i8 by closing a normally open switch |8| which is in parallel or shunt with switch |88,

within the short time interval between the time that the disconnecting arms 1, 8 and 8 are operated following a second successive opening operation of interrupting contacts 5 and 8 by opening Y normally closed switch |82 which prevents reenergization of isolating switch reclosing interlock Pistons |85 and |88 are interconnected by a plurality of links |81, |88 and a plvotally mounted lever |88 rotatable with a shaft |80 mounted on xed pivots. The pistons |88 and |88 are so interconnected that when piston |88 is at the lefthand end of cylinder |83, piston |88 is at the right-hand end oi cylinder |84. A spring |8| in cylinder |88, the tension of which may be controlled by adjustable means |82, normally biases the pistons |85 and |88 to the positions indicate in Fig. 2.

Specially constructed piston |85 includes a port |93 leading from the working face of the piston to an annular chamber |88 intermediate the ends of the piston. When uid under pressure is admitted to cylinder |88 through conduit |85 the pressure must first build up in bore |93Land annular chamber |98 before the piston begins to move. The piston |88 therefore picks up speed slowly and does not receive a high initial velocity as it might were it impacted by a suddenly released pressure front against a full piston face. After a short initial travel, piston |85 uncovers an opening |88 tapped in the sidewall of cylinder |88 which in this case is illustrated as connected with an accumulator chamber |81, although an oriiice alone or none at all may be suillcient for diierent reclosing times. It is obvious that the size of the accumulator chamber |81 will control to some extent theA desired time delay in the operation of pneumatic reclosing relay |18. At approximately two-thirds of the ,stroke of ,piston |85 the port |88 is again covered and the speed of piston 85 increases to complete the stroke against the increasing pressure of return spring |8|. It is obvious that widely varying traveling time characteristics may be obtained by controlling the bore of opening |88 or the size of accumulator chamber |81.

Rotatable shaft |98 has mounted thereon cams |88 and |88, respectively. Cam |88 is adapted to control switches |8| and |82, while cam |88 is adapted to control switch |80. These cams are arranged so that switch is opened a predetermined time in advance of the closing of switch |8| or the opening of switch |82. At the end of the reclosing cycle spring |8| returns the cams |88 and |88 to their initial positions. In this regard it is desirable that all of the switches |80, |8| and |82 be reset at approximately the same time which may be accomplished in a manner disclosed in the above mentioned Boisseau and Beatty application, Serial No. 565,833.

Pneumatic reclosing relay |18 is supplied with fluid under pressure to cause operation thereof in response to every circuit breaker operation. To this end it is preferably connected with conduit 282 with time delay reservoir 200.' Preferably time i delay reservoir 200 is provided with an adjustable escape port 203. By proper proportioning oi time delay reservoir 200 and escape port 288 control of the initial operation of pneumatic reclosing relay |19 is provided; Check valves 20| and 202 prevent the flow of iluid from accumulator reservoir 200 back to conduit 88 or from cylinder |88 back to time delay reservoir 200.

Under certain conditions it may be desirable to move disconnecting arms 1, 8 and 8 when no fluid under vpressure is available to operate the opening and closing fluid motors. 'Ifo this end a manualoperating device-generallyI indicated at 208 is provided. This manual operating device is removable and when employed is associated with the gear 88 for controlling the rotation of the disconnecting arm' 8. This manual operating device includes a crank 208 and a gear mechanism including a pinion 208 for meshing with gear 38. Rotation of crank 208 will rotate gear 38 and consequently will operate the disconnecting arms 1, 8 and 8. It is advantageous that this manual operating device also provide means for releasing either the closing locking arm 18 or the opening locking arm 88 prior to applying a driving force on the gear 88. Accordingly there is provided a bell crank 201 pivtally mounted at 208 and a bell crank 208 pivctally mounted at 2|0. Initial rotation of thehand crank 205 causes the device 208 to tilt bodily about the axis of the pinionk 208 during which movement the devices projecting pin 208.I engages the crank 201 thereby rotating the lockmeans such as a green lamp 2|8, and a resistor 2|8. across the potential source 2|8. When the circuit breaker is open the indicating means 2|8 will be energized. Similarly. circuit breaker a switch. is connected in series with indicating means illustrated asa red lamp i1 and resistance `2|8 across potential source 2|8. When the circuit breakenis closed as is illustrated in Ig.

2, "a" `switch 88 is closed and the red lamp 2|1 `is lighted.

In order toinitiate a switching closed opera. tion trom remote control panel or the circuit ,breuken a manual closing switch 2|8 is providing 228 of a blocking relay 22|y which controls v normally, closed contacts 222 and is provided with tine delayameans 228 to provide a short time deing arm 16 out of engagement with the roller 8I.\ 40

This tilting disengaging movement of the device 208 is arrested when crank 201 engages the xed stop 2|2 so that further rotation oi the. hand crank 208 becomes effective to turn the gear 88 thereby opening the disconnecting arms 1. '8 and 9. Conversely, when manually closing the breaker the initial tilting movement of the device 208 unlatches the locking arm 88, through the agency oi bell crank 208, preparatory to pick.. ing up the drive between the gear and rack mechanism. The manual operating device 208 forms no part of our invention and is disclosed and claimed in copending Gayer application. Serial No. 565.836, filed November 30, 19.44. now Patent Number 2,418,704, issued April 8, 1947, and assigned to the same assignee as the present ap- Dlication.'

The electrical control system of our invention is schematically illustrated in Fig. 3. It should be understood that this electrical circuit should be superimposed on Fig. 2 but was omitted from Fig. 2 in ord'er to simplify the drawings. The corresponding electrical portions of Fig. 2 are designated by the same reference numerals in Fig. 3. Both Figs 2 and'3 illustrate the control devices in the operating condition corresponding to Fig. 1, that is, with breaker closed. control bus energized and with tanks charged with compressed air at operating pressure. A source of direct current control potential is schematically designated in Fig. 3 as 2|8. A suitable switch 2|8 controls the connection of the source 2|8 with the control circuits. The "b limit switch y81, which is open when the circuit breaker is closed, is connected in series `with an indicating lay for reclosing of contacts 222. Closing oi' switch 2|8 also energizes winding so of the clos. ing cutoit switch generally indicated at 88.

The minimum opening pressure switch |2| controls the energization oi an auxiliary relay 228 having two normally closed sets of contacts 228 and 228. Minimum reclosing pressure switch |22 controls the energizatlon oi' an auxiliary relay 221 having a normally closed set of contacts 228 and a normally open set oi' contacts 228. The normally open set of contacts 228 are adaptedto control the energization oi' an indicating means generally indicated at 280 so that when the fluid under pressure in the tanks i8, I8 and 28' drops below the value determined by minimum reclosing pressure switch |22 the operator will be apprised oi this fact. Minimum closing pressure switch |28 also controls the energizatioroi an auxiliary relay 23| having normally closed contacts 282 and normally open contacts 288. The normally open contacts 283V when closed are adapted to energize an alarm or indicating means switch 288 is released. It is obvious that thecontacts of an automatic protective relay may be substituted for, or shunted around, the tripping switch 288 for service conditions where automatic reclosing is not required. -V

In order to operate the circuit breaker'to the open position in response to an abnormal curr'entoondition. a suitable relay (not shown) is provided which controls a switching member schematicallyindicated at 288 for bridging contacts 288.

A double pole, manual selector switch 28| is i provided to determine whether or not the operating mechanism will operate to reclose the circuit breaker after being automaticallytripped open. In the position indicated in Fig. 3 reclosing of the circuit breaker will result, whereas if switch 28| is moved to its other position thereby preventing operation of isolating switch interlock valve 88, reclosing of the circuit breaker will not occur because opening of the isolating arms 1, 8 and 8 will take place immediately follow-- ing interruption by the retracting contacts.

In view of the detailed description included above the operation oi the control system will be obvious to thcse'skilled in the art, and a relaassassin tively brief description will be included hereinafter. The control system of our invention will enable the circuit breaker to perform the following operations. (1) electrically controlled opening operation; (2) electrically controlled closing operation; (3) trip free operation; (4) reclosing trip operation, and (5) hand trip operation.

The opening operation of the circuit breaker consists of a single sequential operation of the arcing contacts in interrupting units 2. 3, 4l and the disconnecting contacts serially connected therewith. Assuming that the circuit breaker is in closed position indicated'in Fig. 3 but with the selector switch 24| of Fig. 3 moved to the oppof site position from. that shown.' a tripping operation may be initiated either by closing trip switch 233 or by the bridging of contacts 240 by switch 233 upon operation of a suitable relay connected to switch 233. With the pressure in tanks |3, i3 and 20 being suillciently high so that all of the minimum pressure relays |2I. |22 and |23 are in the positions indicated in Figs. 2 and 3. the blast valve windings ||3, i1 and ||3 will be energized in response to operation of switch 233 or bridging of contacts 240 and consequently the three blast valves 32 will open. Such opening of blast valves 32 will cause seal in contacts |20 to be closed and also will cause fluid under pressure to flow to each of the interrupting units 2. 3 and 4 to interrupt the circuit at the arcing contacts contained in these units. Simultaneously, air will also now through conduit 33 to the reclosing relay |13 and to the pneumatic interlock 30. In view of the fact that selector switch 24| is moved to the other position from that shown in Fig. 3, the winding |13 ci isolating interlock valve 33 cannot be energized and if iluid under pressure exists in all of the blast valve conduits 23, fluid under pressure flowing through conduit 34 opens circuit breaker opening valve 43. As soon as valve 43 has opened it is held open by latch thereby divorcing subsequent action of opening valve 43 from the pressure in blast valve conduits 23. The opening of circuit breaker opening valve 43 permits fiuid under pressure to flow into cylinder 13 to release lock open means 31 and also permits indicated in Figs. 2 and 3, closing of the circuit breaker may be initiated by depressing close switch 2 I3 which causes energization of the winding of closing cut-on switch 33 and a consequent closing of normally open contacts 33. The closing of contacts 33 completes the circuit of winding |3| of circuit breaker closing control valve 43 through contacts 33 which are also normally closed when the circuit breaker is open. The opening of circuit breaker closing control valve 43 closes seal-in contacts |34 and furthermore permits fluid under pressure to iiow both to the circuit breaker closing cylinder 44 and to the circuit breaker lock open means 33. The supply of fluid under pressure to the circuit breaker lock open means 33 releases locking member 33 and .f allows piston 43 to close the disconnecting arms fluid under pressure to enter cylinder 42 of the circuit breaker opening fluid motor. In the meantime. although contact |30 of the pneumatic reclosing relay |13 has opened, it is cut-of! switch contact |41 that opens to deenergize the blast valve windings |13. H1 and lil, as a consequence of which blast valves 32 are closed. This is due to having previously set switch 24| to the left. The high Pressure air in blast conduits 23 exhausts to atmosphere and the arcing contacts 3 and 3 are reclosed by virtue oi the action of springs 23 and 24, respectively. Before arcing.l contacts 3 and 3 reclose, the disconnecting contact arms 1. 3 and 3 have operated to insert an isolating gap in series with each interrupting head 2. 3 and 4, respectively. When the operating rod 33 connected with the disconnecting arms 1, 3 and 3 has reached the end of its opening stroke the locking member 33 moves into locking position and extension |13 releases latch |10 so that circuit breaker opening valve 43 may close. This arrangement insures that the circuit breaker opening valve 46 remains open until the mechanism travel is completed. Since the contacts 33 are held open by air pressure from the opening control valve flowing through conduit 32 to actuate plunger 98 during the circuit breaker opening operation, it is not-possible to energize the 1, 3 lancl 3. At the end of the closing stroke the hold closed locking arm 13 moves into locking .position and arm 31 mechanically opens cut-oil' switch 33 to deenergize winding |3| o! closing control valve 43. In addition to controlling the condition of contacts 33 winding 30 of closing cut-ofi switch 33 also acts as an anti-plump device by holding the contacts of the closing cutof! switch 33 open after they have once been sepa.- rated. As long as the closing control switch 2|3 remains closed contacts 33 will remain open and no further closing operations oi' the circuit breaker can occur. The details of the anti-pump device and closing cut-oil' switch are fully described in Boisseau Patent 2,346,147 referred to above.

An electrically controlled trip free operation of the circuit breaker is merely a closing operation followed immediately by a normal opening operation. This type of operation will occur when the breaker is closed in on a fault. To insure that the opening control circuit can be established before the circuit breaker is completely closed the opening cut-off switch |41 substantially identical with the arrangement disclosed inthe Schneider patent referred to aboveI is provided. With this arrangement and particularly by virtue of dog |52 on switch |43 the opening control circuit is established considerably before the breaker is in the system energizing position. When the disconnecting switches 1. 3 and 3 are opening switch |41 causes the opening control circuit to be deenergized shortly after the start of motion thereby saving considerable air on reclosing trip operations. Since trip free operations normally occur when the circuit breaker is closed on an overloaded system the breaker control circuit is arranged to perform onlyl a straight opening operation immediately after closing.

The time de'lay reclosing blocking relay 22| holds open the single shot reclosing circuit for an interval of one second after the breaker isolating switch has closed. As was mentioned above the closing cut-on switch 33 causing operation of the switch controlling contacts 33 prevents pumping .of the circuit breaker. The opening operation is given definite preference over the closing operation by `virtue of the fact that contacts 33 are opened pneumatically by piston actuated plunger 38 whenever opening control valve 48 is opened. The reclosing trip operation of the circuit breaker consists of two successive openings of arcing or interrupting contacts and 8 followed bythe opening of isolating or disconnecting contacts arms 1, 8 and 8. With the seilectoi switch 24| set in the position shown in Fig. 2 a reclosing operation is initiated by the bridging of contacts 240 by switch 239. Bridging of contacts 240 causes energization of the blast valve windings ||8, ||1 and I i8, with the consequent opening of the blast valves 32 and the bridging of seal-in contacts |20. At the same time winding of isolating interlock valve 65 ,is1 also energized through contacts 231, |36, 228, selector switch 24|, switch |82, and contacts 222 with, the consequent "blocking of `passageway 84 leading to circuit breaker opening valve 46. The circuit breaker opening control valve 46fcannot operate and consequently the isolating switch contact arms 1, 8 and 8 cannot operate but otherwise the circuit A switch |82 deenergizes the winding |18 of isolating interlock valve 65 while the closingof switch |8| reestablishes the blast valve circuitfor windings H6, ||1 and ||8 in parallel with switch |80. Switch |82 must remain open a suillcient time after the interruption of the circuit to insure that relay controlling contacts 24||have dropped out to open switch 239. The reclosing relay |18 controls the time which must elapse before reclosing operation can occur. If the system fault persists the breaker will then perform a straight opening operation since the opening of switch |82 deenergizes'winding |16 and permits the isolating interlock 465 to 'open' whereupon the circuit breaker opening valve 48 may be opened and an opening operation as has been described above, occurs. Initial movement of the disconnecting arms 1, 8 and 3 operates switch |48 to deenergize the blast valvewindings ||6, ||1 and ||8 with the resultant closing of blast valve 32. In the -event that the fault is a temporary one and is cleared by the operation of arcingA contacts 5 and 8 the reclosing relay |19 will complete its cycle and reset to the position indicated in Fig. 2 with the breaker remaining in the closed position.

v A manual trip operation of the circuit breaker like the electrical openingA operation outlined above consists of a single sequential operation oi' the interrupting and isolating contacts. When manual trip pull rod |3| is actuated pilot valve |29 is opened and if the pressure is suiliciently high to insure a satisfactory opening operation pistons |38, |39 will move upwardly to open the passageway between conduits and |28 whereupon by virtue of pistons ||2 the blast valves 32 are opened in exactly the same manner as if windings ||6, ||1 and ||8 had been energized electrically. To close the blast valves 32 rapidly and conserve ain during hand trip operations, the

l hand trip valve comprising piston |38 is closed mechanically during the initial motion of discon- .necting arms 1, 8 and 9 by virtue of cam |44 .amena i which engages a roller |45. Lever |43 holds pilot breaker functions the same as in -a normal openvalve |29 open once it has been opened until the .hand trip valve islclosed by cam |44.

It will be apparent to those skilled in the art that our invention is not limited to the particular construction shown but that changes and modifications may be made without departing from the spirit and scope of our invention and we aim lin the appended claims to cover all such changes and modifications.

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. In a multipole circuit breaker having serially connected interrupting and isolating contacts for each pole thereof, means including a first fluid motor for each pair of interrupting contacts. a source of fluid 'under pressure, means including a conduit for each pole of said circuit breaker for connecting said sourcex with each of said fluid motors to open said interrupting contacts, a second fluid motor for opening said isolating contacts, means including a valve for controlling the supply of fluid between said source and said secl ond fluid motor, fluid operated means for operating said valve, fluid conducting means connected to said fluid operated means and having a separate connection to atmosphere for each of said and for establishing a connec on between the..

associated conduit and said fluid operated means.

2. In a multipole circuit breaker having serially connected interrupting and isolating contac for each pole thereof, means including a first fluidk motor for each pair of interrupting contacts, a sourcecf fluid under pressure, means including a conduit for each pole of said circuit breaker for connecting said source with each of said fluid motors to open said interrupting contacts. a second fluid motor for opening said isolating contacts, means including a valve for controlling the supply of fluid between said source and said second fluid motor, fluid operated means for operatingr` said valve, fluid conducting means connected to said fluid operated means and having -a separate connection to atmosphere for each of said conduits, and separate fluid pressure valve means associated with each conduit and responsive to a predetermined fluid pressure therein for shutting oil.' the separate connection to atmosphere for the associated conduit and for establishing a connection between the associated conduit and said fluid operated means.

3'. In a' multipole circuit breaker having serially connected interrupting and isolating contacts for each pole thereon-means including a flrst fluid motor for each pair of interrupting contacts, a sourceof fluid under pressure, means including a conduit for each pole of said circuit breaker for connecting said source with each of said fluid motors to open said interrupting contacts, a second fluid motor for opening said isolating contacts, means including a valve for controlling the supply of fluid between said source and said second fluid motor, fluid operated means for operating said valve, yfluid conducting means connected to said fluid operated means and having a separate connection to atmosphere for 'eachof said conduits, andl separate plunger operated valve means associated with each conduit and responsive to a predetermined fluid pressure therein for shutting oil? the separate connection to atmosphere for the associated conduit and for estab- 

